As is known in the art, many semiconductor devices, such as Field Effect Transistors (FETs) include Schottky contact structures. For example, many FETs include a gate to control a flow of carriers between a source and a drain through a channel region in a semiconductor, such as a Groups III-Nitride semiconductor, One type of FET (FIG. 1) is a Gallium Nitride (GaN) FET having: a gate contact; and, an electrode; the gate contact having: a bottom metal of nickel (Ni) in Schottky contact with an AlGaN semiconductor layer and a low resistance electrode, such as gold (Au) with a barrier layer, such as Platinum (Pt) to protect against metal migration between the Au and the Ni. During high temperature operation of the GaN FET with Ni/Pt/Au Schottky gate, Au can migrate/diffuse from the edges of the gate metal structure into the AlGaN and cause gate leakage, Prior attempts included the use of Nickel oxide in place of the Ni/Pt, a post deposition anneal process, or making the Ni and Pt layers up to 4000 A thick. However, none of these approaches are compatible with high yield manufacturing of the GaN FET using photolithographic liftoff technique.